Hybrid Perovskite Ferroelectric Enables Dual‐Polarity Polarization‐Sensitive Photodetection Toward Encrypted Communication

Abstract

Polarization‐sensitive photodetectors enable effective information transmission in the field of optical communications by identifying the polarization state of linearly polarized light (LPL). Dual‐polarity photodetectors are capable of generating controllable photocurrent signals with discrepancies of polarities at multiple levels. The combination of dual‐polarity photoresponse and polarization‐sensitive photodetection may offer a potential solution for encrypting polarization information. Here, dual‐polarity polarization‐sensitive photodetection is successfully achieved in a bilayer hybrid perovskite ferroelectric (2TMA)2(MA)Pb2I7 (2TM‐2; 2TMA = 2‐thiophenemethylammonium, MA = methylammonium). The alteration of the ferroelectric polarization direction results in corresponding changes in the anisotropic photoresponse driven by the bulk photovoltaic effect. The photocurrent anisotropy ratio ω (17.7) of 2TM‐2 is the largest among the reported lead iodide perovskite single crystal devices. Specifically, an encrypted LPL communication model is proposed based on this switchable dual‐polarity polarization‐sensitive photosensitive detector and simulates the encrypted transmission process of capital letter “LPL” signals. This work offers new insights into the electrical control of polarization‐sensitive photoresponse in hybrid perovskite ferroelectrics and is expected to have a transformative impact on the field of secure communication technology.